Primary Lens Luxation (PLL)

What is P.L.L

Primary Lens Luxation (PLL) is a well-recognised, painful and blinding inherited eye condition that affects many breeds of dog, particularly terrier and terrier-type breeds. In affected dogs the zonular fibres which support the lens breakdown or disintegrate, causing the lens to fall into the wrong position within the eye. If the lens falls into the anterior chamber of the eye glaucoma and loss of vision can quickly result.

DNA testing is now offering examines the DNA from each dog being tested for the presence or absence of this precise mutation.

Breeders will be sent results identifying their dog as belonging to one of three categories:

CLEAR: these dogs have two normal copies of DNA. Our research has demonstrated clear dogs will not develop PLL as a result of the mutation we are testing for, although we cannot exclude the possibility they might develop PLL due to other causes, such as trauma or the effects of other, unidentified mutations.

CARRIER: these dogs have one copy of the mutation and one normal copy of DNA. Our research has demonstrated that carriers from some breeds have a very low risk of developing PLL. The majority of carriers do not develop PLL during their lives but a small percentage do. This has been particularly noted for the Miniature Bull Terrier during our study and is also suggestive in the Lancashire Heeler. For Tibetan Terriers our study did not show any evidence to suggest that carriers will develop PLL. For the Miniature Bull Terrier we estimate that between 2% and 20% of carriers will develop the condition, although we believe the true percentage is nearer to 2% than 20%.

GENETICALLY AFFECTED: these dogs have two copies of the mutation and will almost certainly develop PLL during their lifetime. We advise that all genetically affected dogs have their eyes examined by a veterinary ophthalmologist every 6 months, from the age of 18 months, so the clinical signs of PLL are detected as early as possible.